Temp Guage - Problem...?

[rlpjw1959]

Temp Guage - Problem with OD...?

I have a 89 First Gen. V6 SR5 171K miles. It was overheating and mechanic replaced radiator with all related parts. I think the radiator is a larger one. This took care of the problem and it has never had an overheating problem since. 6 Months ago. (pic enclosed is a hot as the guage will ever get)

Now the problem. Ever since this has happened my OD will take a long time to start to work (it used to go in to OD before I got to the end of my street). And on a cold day after I get on the hwyway it seems like the cold air moving through the radiator cools off something and the OD kicks off never to return. On Hot days doesn't seem to happen as much and will the OD will work.

I have had the thermostat replaced but with same results. When I tell the story to my mechanic he says I need to talk to a transmission guy and that it could not be the cooling system.

Any help on this would be great. It is a real drag going down the Highway @ 3000 RPMs. Not to mention my MPG is at about 13 right now. I can't afford to have these guys start swapping parts on me, could get expensive..!

Thanks in advance...

 

[92-SR5]

I don't know much about automatic transmission, but I would check my tranny lines and cooler. Is it electronically controlled?

 

[Bad_Vision]

you could try swapping out the thermostat for a different temp one. the OD engages at 176 degrees so you need a 180 degree thermostat. if you have a 180 degree youll need to step up to a 195

 

[rlpjw1959]

Badvsion - does the temp gauge not getting to half way (per the pic) indicate that the truck is not getting up to the temperature it needs to? I'm going to check into the 195 degree thermostat. Any other ideas would be great. Thx

 

[Bad_Vision]

get a thermoprobe and check the temp at the coolant sensor

 

[rlpjw1959]

Does it require special equipment?

Where is the source that I measure...?

By the way I did have the mechanic replace the thermastate. But I don't know if it was just the same kind. Putting in a thermostat that will get hotter sounds right to me. ( not sure the correct terminology) it will go into OD but when I get on hwy it kicks off because the cold air. after I get off the hwy sit at a light for a few minutes it will come back on. And it does take longer for OD to come on. it use to come on immediately...before the new Radiator etc.

Sorry for the rambling...

 

[Bad_Vision]

inferred temperature sensing guns work, hell even a grill thermometer works just stick it next to the coolant sensor on the thermostat housing when the truck is good and worm it will give a idea of what temp the coolant is and if its lower 165 at idle you may need 195.
but now that you say the highway i would recommend this trick, take a piece of thin aluminum about 2inches tall and fix it to the bottom outside(facing bumper) of the radiator this will keep the temp higher as it blocks a small portion of the wind while your cruising down the highway but wont effect your slow speed temp.

 

[rlpjw1959]

BV - So If I put the wind block on radiator and the OD stays on... Like it should. that would confirm that the cold air is dropping the temp to disable OD.

So then what do I do...? How do I correct it?

Thanks!

 

[Bad_Vision]

you keep the wind block in and trim it to find the perfect medium between having enough heat to keep the OD on and keep the engine cool.
happy testing!!!